A stepping motor having a lead screw which is formed on a tip end side of a rotation shaft protruding from its stator has been conventionally used for moving a lens and the like provided in an optical pickup device used in a CD or a DVD player or provided in a camera. As this type, a stepping motor has been known in which a tip end part of a rotation shaft is supported by a bearing and a flat spring (see, for example, Japanese Patent Laid-Open No. 2007-104849, Japanese Patent Laid-Open No. 2005-269733, and Japanese Patent Laid-Open No. Hei 6-98522).
In the stepping motor described in the above-mentioned Patent References, a bearing held by a frame, which is fixed to a stator, supports a tip end part of a rotation shaft in a radial direction. Further, in this stepping motor, a flat spring is abutted with the tip end of the rotation shaft to urge the rotation shaft in an opposite-to-output side so that the flat spring supports the tip end part of the rotation shaft in a thrust direction (axial direction). The bearing is fixed to the frame by press-fitting or the like. In this stepping motor, an engagement part for engaging with the frame is formed in the flat spring and the flat spring is attached to the frame by utilizing elastic deformation of the engagement part.
The rotation shaft is generally formed of stainless steel in many cases because a small surface roughness and a high abrasion resistance are required in the lead screw portion which is formed on the rotation shaft. Further, the flat spring is also generally formed of stainless steel plate in many cases.
As described above, both of the rotation shaft and the flat spring are often formed of stainless steel. However, in the stepping motor described in the above-mentioned Patent References, the flat spring for supporting the tip end part of the rotation shaft in the thrust direction is abutted with the tip end of the rotation shaft. Therefore, in this stepping motor, for example, when the rotation shaft and the flat spring formed of stainless steel are used, the same type of metals are slid or contacted with each other during rotation of the rotation shaft. As a result, in this stepping motor, noise is easily occurred at the time of rotation of the rotation shaft and abrasion is easily occurred in the rotation shaft and the flat spring and thus its durability is not satisfactory.